​Design for design!?! How does that work?

A technique you use as an engineer and probably do not even realise

You have likely heard of design for manufacturability, design for sustainability, design for servicing and design for recycling. You can also work out what each is about. You have likely also heard of “design for X”. Where you substitute X for whatever is important to you.
 
But have you heard of “design for design”?
 
It seems an odd concept, but you have probably already done it. Maybe it was for the best, and maybe not – but I will talk about that later.
 
In design for design, we make a design decision early on in the engineering process so that the rest of the design task is easier. For example:

• A team designing a race car on a limited budget (for both time and money) specifies that they will design a space frame instead of a monocoque. Thus, the analysis process and adjustments of the design to accommodate ongoing changes in other subsystems are easier. Making the overall design project easier.
• An engineer who needs to develop a seal between two existing parts decides on the use of silicone tooling and polyurethane so that a complicated shape can be made that works around those other two parts. The seal might be more expensive to produce and maybe more time consuming to install, but the design process is now faster and easier because there is only one part to be designed as opposed to three. This implies that time or design budget were limited.

 
You have likely noted in the above that there is some external reason that mandates the design be completed quickly. Therefore, the engineer makes decisions that will make the design process faster. You could also argue that this is actually part of the development of the design brief – and not design. But given things such as coevolution, there is actually no clear definition of when the brief development ends, and the design process starts. And one could argue that a design brief could also be designed – potentially another example of design for design that has been happening in engineering all along.
 
And this all seems reasonable – although not always ideal – it would be good to always have the time and resources to implement an optimal engineering solution.
 
However, what about times when design for design is not reasonable?
 
And have you been guilty of this?
 
Some other examples of design for design:

• An engineer dislikes sheet metal parts – such parts are not precise and this engineer has mild OCT – so all parts are designed for machining.
• An engineer enjoys designing with surfaces in CAD so creates parts with convoluted shapes that justify the use of surfaces. The official reason for the convoluted shapes is aesthetics and stress minimisation.
• An engineer in a design house contracted to develop a tool set for a market niche chooses to design new metal forgings (as opposed to just custom over-mouldings for existing forging) because they are excited by the notion of designing hand tools from scratch.

The above examples show that sometimes design for design is not about making the design process easier, but, instead, about making the design process more enjoyable.
 
By the way – I have witnessed all of the above examples firsthand.
 
So next time you are making some early decisions for how you will go about tackling an engineering challenge (and designing for design), ask yourself if you are doing it to make the process more efficient or just more enjoyable.